如何在 soci 中获取 table 的架构或行名称?
How can I get the schema or row names of a table in soci?
我正在尝试完成 ,并且我知道如何间接完成...如果我可以获得 table 的架构。
如何使用 soci 执行此操作?
我试过:
std::string i;
soci::statement st = (mSql->prepare <<
"show create table tab;",
soci::into(i));
st.execute();
while (st.fetch())
{
std::cout << i <<'\n';
}
但只打印了 "tab"。
我也试过这个,来自 GitHub 中的 Soci 文档:
soci::column_info ci;
soci::statement st = (mSql->prepare_column_descriptions(table_name), into(ci));
st.execute();
while (st.fetch())
{
// ci fields describe each column in turn
}
但被告知 column_info 不是 soci 的成员。
我找到了下面的代码here
soci::row v;
soci::statement st = (mSql->prepare << "SELECT * FROM tab", into(v));
st.execute(true); /* with data exchange */
unsigned int num_fields = v.size();
std::cout << "fields: " << num_fields << std::endl;
num_fields = (num_fields <= 9) ? num_fields : 9;
unsigned long num_rows = (unsigned long)st.get_affected_rows();
std::cout << "rows: " << num_rows << std::endl;
for (size_t i = 0; i < num_fields; ++i) {
const soci::column_properties &props = v.get_properties(i);
std::cout << props.get_name() << '\t';
}
std::cout << std::endl;
最后打印的是列的正确名称。
我正在尝试完成
如何使用 soci 执行此操作?
我试过:
std::string i;
soci::statement st = (mSql->prepare <<
"show create table tab;",
soci::into(i));
st.execute();
while (st.fetch())
{
std::cout << i <<'\n';
}
但只打印了 "tab"。
我也试过这个,来自 GitHub 中的 Soci 文档:
soci::column_info ci;
soci::statement st = (mSql->prepare_column_descriptions(table_name), into(ci));
st.execute();
while (st.fetch())
{
// ci fields describe each column in turn
}
但被告知 column_info 不是 soci 的成员。
我找到了下面的代码here
soci::row v;
soci::statement st = (mSql->prepare << "SELECT * FROM tab", into(v));
st.execute(true); /* with data exchange */
unsigned int num_fields = v.size();
std::cout << "fields: " << num_fields << std::endl;
num_fields = (num_fields <= 9) ? num_fields : 9;
unsigned long num_rows = (unsigned long)st.get_affected_rows();
std::cout << "rows: " << num_rows << std::endl;
for (size_t i = 0; i < num_fields; ++i) {
const soci::column_properties &props = v.get_properties(i);
std::cout << props.get_name() << '\t';
}
std::cout << std::endl;
最后打印的是列的正确名称。